Passenger vehicles, light trucks, and heavy duty trucks may in some examples include an ability to support 110V-120V alternating current (AC) and 220V-240V AC electrical loads. As an example, such vehicles may support electrical loads (power take-off device) up to around 450 Watts, and in the future may support electrical loads from 2 KW-8 KW and potentially higher (e.g. 16 KW and greater). Systems for such vehicles may include designs for directly supporting such appliances either while the vehicle is stationary, for example for use at a job site or for supplying electricity to home electrical loads, or while the vehicle is moving, for example to power a refrigeration unit. Such systems may comprise direct current (DC) to AC systems, and may be referred to as a power to the box (Pt.) system. Such Pt. systems may be driven either by an alternator, a belt-integrated starter generator (BISG) driven by the engine or by a high voltage battery (e.g. 300V-350V) which is in turn charged by a crank ISG (CISG).
Various approaches are provided for operating a device (electric load) using power generated from engine operation. In one example, as shown in US 20180344545, Khadafy et al. teaches operation of a lifting mechanism such as a ramp and chairlift using power from an on-board battery. An on-board generator generates electrical energy from engine torque which is stored in the battery. During operation of the lifting mechanism, even if all conditions are met for initiating an engine idle stop, the idle stop may be delayed until completion of the operation of the lifting mechanism.
However, the inventors herein have recognized potential issues with such systems. As one example, multiple operations of a power take-off (PTO) device may take place successively and by idle-stopping the engine after completion of the first operation of the PTO, subsequent operations of the PTO may be disrupted. Further, the PTO operation may be optional for the operator and he may not desire operation of the PTO device when conditions are met for idle stop. Also, indefinite delaying of engine idle-stopping for PTO operation may not be desired by the operator.
In one example, the issues described above may be addressed by a method for a vehicle comprising: during operation of a generator, in response to a condition for an engine idle-stop being met, schedule engine shut-down based on input from a user. In this way, based on user input, engine idle-stop operations may be better coordinated with generator operation.
As an example, power generated by a generator driven by the engine may be used to operate a power take off device such as a cement mixer, a trash compactor, a harvester, a snow ploughs, mobility device, etc. During operation of the PTO device, the generator is operated to convert mechanical energy (from engine torque) to electrical energy for charging the battery. In response to conditions being met for an engine idle-stop, if a generator is not operational, the engine may be idle-stopped until conditions are met for engine restart. In response to conditions being met for an engine idle-stop, if a generator is in operation, the user may be prompted to select if the engine would be stopped or continued to operate (override idle-stop). The idle-stop override may be continued until the generator operation stops and the vehicle moves. The user may also select an option to override idle-stop for a specific time period after which irrespective of generator operation, the engine may be stopped if conditions for idle-stop continue to be met.
In this way, during generator operation, by scheduling idle-stop based on operator input, operation of a PTO device may be effectively continued without interruption due to power shortage caused by engine shut-down. By continuing to operate the engine until the vehicle moves, successive operation of the PTO may be supported. The technical effect of allowing the operator to select a specific duration for idle-stop override is that the operator may operate the PTO device for a desired duration and then allow engine idle-stop which would improve fuel efficiency. Overall, by adjusting generator operation and engine idle-stop based on operator input, customer satisfaction may be improved.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.